Have you ever watched a movie on mute? It's lame. Luckily, movies have music.
John Williams is one of the most famous composers of all time. Think of your favorite movie-- he probably wrote the music for it. If you don’t believe me, take it from his over 50 Oscar nominations (he’s the second most nominated person in history, just behind Walt Disney.) Williams hasn’t had any big hits in a while but his score for "Star Wars: The Force Awakens" definitely brought him back into the limelight. That is, if he ever left it.
Hans Zimmer is like John Williams' edgier younger brother who spends a lot of time in his room messing with the synth he made out of an old rotary phone and a car battery. Zimmer’s work is moody, experimental, and often becomes the defining trait of the movie. His filmography is huge, but some of his best stuff comes form his work with director Christopher Nolan. He’s even credited with popularizing the braaams (yes, that’s a real term) commonly used in action movie trailers.
Howard Shore is the mastermind behind all the “Lord of the Rings” music (including all three “Hobbit” movies!) That’s basically his entire filmography but, come on, it’s “Lord of the Rings.”
Alexandre Desplat has racked up eight Oscar nominations and one win in the last decade alone. His work on “Moonrise Kingdom” and “Grand Budapest Hotel” won him a spot as Wes Anderson’s golden child, and he is now working on a mystery movie with the director. He also wrote all of the saddest music in “Harry Patter and the Deathly Hallows”, so it’s fair to blame him for every time those movies made you cry.